Polyether polyols are useful intermediates for the production of polyurethanes. Polyurethanes can be transformed into aromatic amines and polyether polyols by basic hydrolysis. A largely unanswered question is how to best use polyether polyols recovered from polyurethanes. One approach is to purify and reuse the polyols, but purification is costly and often impractical. Another potential approach is to depolymerize the polyether polyol to give low molecular weight products using an ether cleavage reaction. Unfortunately, ether cleavage typically requires harsh reagents such as concentrated sulfuric acid and hydriodic acid, and is not commercially practical.
Ganum and Small (J. Org. Chem. 39 (1974) 3728) showed that aliphatic ethers react under mild conditions with acetic anhydride and ferric chloride to give esters. Aliphatic ethers also react with acid chlorides in the presence of Lewis acids to give esters, but alkyl chlorides are also produced. These reactions have apparently not been applied to polyether polyol depolymerization.
Crude polyether polyols recovered from polyurethanes usually contain many impurities. The polyols are hard to purify because of their typically high viscosities and high molecular weights. Distillation, an effective technique for purifying low molecular weight compounds, is usually not practical for polyols because of their low volatility. Of great value would be a practical way to convert polyols to low molecular weight products that are easily purified by distillation.